Non-common-node gridding technology

Abstract

The invention relates to a finite element gridding technology in the field of welding simulation, in particular to a non-common-node finite element gridding technology. In a traditional finite element gridding method, a node sharing mode is usually adopted, and the problems of calculation errors and insufficient precision are easily caused by the method. The invention innovatively provides a non-common-node gridding technology, so that errors caused by node sharing are avoided, and the simulation precision is remarkably improved. By means of the technology, complex physical phenomena in the welding process can be simulated more accurately, and particularly obvious advantages are shown when the problems of thin plate treatment, weld joint quality, welding deformation and the like are solved. The technology not only improves the welding simulation precision, but also effectively improves the calculation efficiency, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the field of welding simulation technology, and in particular to a non-shared node meshing technology. The technology is mainly used in numerical simulation and simulation calculation in the welding process, especially in the analysis of welding heat input, thermal deformation, residual stress, etc., which can effectively solve the problem of node sharing in traditional meshing methods and improve simulation accuracy and calculation efficiency. Background Art

[0002] In traditional welding simulation, the meshing process usually uses the common node technology, that is, the mesh units of the weld and the base material share the same nodes, thereby simulating the connection relationship between the weld and the base material. This method can be well applied in simple welded structures and simplifies the modeling process to a certain extent. However, when the geometric shapes of the weld and the base material are very different or there are complex structures with multiple welds crossing, the traditional common node technology is difficult to meet the requirements, and the difficulty and quality of meshing significantly affect the simulation accuracy.

[0003] Specifically, the common node meshing method often faces the problem of difficult mesh generation when dealing with complex geometric shapes. The geometric differences between the weld area and the base material area, especially when the weld shape is complex or multiple welds intersect, can easily lead to mesh distortion, distortion or over-stretching, which in turn affects the reliability of the calculation results. In addition, the common node method may cause unreasonable errors in the connection relationship between nodes, making it difficult to accurately capture the true behavior of thermal stress and thermal deformation in complex welded structures.

[0004] More importantly, the common node technology cannot fully consider the interaction and interface effects between different materials during the welding process. The weld and the base material usually have different material properties, such as thermal conductivity, expansion coefficient, etc. The impact of these differences on heat transfer and stress is often not fully reflected in the common node meshing method. Due to node sharing, the transfer and deformation behavior of thermal stress cannot be accurately simulated in the simulation, resulting in the simulation results such as temperature field, stress distribution and residual stress deviating from the actual working conditions, affecting the simulation accuracy and credibility.

[0005] Therefore, although the common node meshing method can provide a basic modeling solution in some simple welding simulation scenarios, its application effect in complex welded structures is not ideal, especially in accurately simulating temperature fields, displacement deformation and residual stress distribution. This has prompted researchers to explore more accurate meshing methods, such as non-common node meshing technology, which can effectively solve the above problems and improve the accuracy and reliability of complex welded structure simulation. Summary of the invention

[0006] The purpose of the present invention is to provide a non-common-node meshing technology to overcome the shortcomings of existing welding simulation meshing technologies, especially the difficulties in meshing and insufficient simulation accuracy encountered when dealing with complex welded structures. In traditional welding simulations, a common-node meshing method is often used, in which the mesh units of the weld and the parent material share the same nodes. This method can be effectively applied to simple structures, but when faced with complex structures such as large differences in geometric shapes and weld intersections, problems such as uneven meshing and poor mesh quality are prone to occur, which in turn affects the accurate simulation of physical phenomena such as thermal stress and deformation in subsequent welding processes, resulting in large deviations in simulation results. Therefore, improving mesh quality and enhancing the accuracy of simulation models have become technical problems that need to be solved urgently.

[0007] In order to solve the above problems, the present invention proposes a non-common-node meshing technology. This technology divides the weld area and the parent material component area into independent grids respectively, avoiding the performance deficiencies caused by the shared nodes of the weld and parent material component grids in the traditional common-node method. Specifically, the grids of the weld area and the parent material component area no longer share any nodes, but are independently divided into grids to ensure that the physical behavior between the two can be simulated independently and accurately. This technical solution can not only smoothly generate high-quality grids in structures with complex geometric shapes, but also more realistically reflect the heat transfer, stress distribution and displacement deformation behavior of different regions, thereby improving the accuracy and reliability of the entire simulation model.

[0008] In addition, the present invention also introduces optimization and adjustment methods in the meshing process, which can effectively generate meshes that meet high-precision requirements, especially in the case of complex geometric shapes and weld intersections. These optimization measures make meshing more flexible and can provide applicable solutions in different complex welding scenarios. Through this technology, the present invention can significantly improve the accuracy of key links such as stress solution and temperature field analysis in welding simulation, and provide a more reliable theoretical basis for welding process optimization and residual stress analysis.

[0009] To achieve the above object, the present invention adopts the following technical solution:

[0010] Step 1: Import the CAD model

[0011] In this step, the user first imports the geometry data required for welding simulation into the simulation system. The user can choose to import STL format files or meshed K files, which usually contain the geometry and size data of the structure. The system will automatically recognize the imported geometry and prepare for subsequent meshing and simulation operations. At this point, the user can select a single part or multiple parts for processing, and the system can support a variety of different file formats (such as STL, IGES, etc.), so that data from different sources can be flexibly processed, providing stronger compatibility and adaptability.

[0012] Step 2: Model surface construction

[0013] After importing the CAD model, the system builds and optimizes the surface of the geometry according to the user's settings. This step is crucial because the geometry needs to be refined in welding simulation to provide basic support for meshing. In this process, users can select the geometry that needs to be simulated according to specific needs and set some parameters (such as surface refinement accuracy, mesh density requirements, etc.). The system automatically generates more accurate surfaces through these parameters. These refined surfaces will help generate higher quality mesh units in the subsequent meshing process. In addition, when constructing the surface, the system will automatically handle defects and irregular areas of the geometry to ensure that subsequent operations can proceed smoothly.

[0014] Step 3: Welding Path Creation

[0015] After completing the surface construction of the model, the user needs to define the welding path. The system will automatically generate welding joints based on the geometry of the upper and lower parts selected by the user, and calculate the optimal welding path according to the welding process requirements. In this process, the system will not only consider the geometric position of the welding joint, but also combine the welding materials, process requirements and the actual situation of the geometry to intelligently solve the most suitable welding path. Users can also manually adjust the welding path to ensure that it matches the actual welding process. In addition, the system will consider the situation of multiple weld intersections and perform appropriate path optimization to avoid unnecessary conflicts and redundancy and ensure the accuracy of the welding process.

[0016] Step 4: Meshing of non-shared nodes

[0017] After creating the welding path, enter the meshing step. In this step, the user can select a suitable non-common node mesh type according to the material properties and geometric shapes of different components. Unlike the traditional common node meshing method, the present invention adopts non-common node meshing technology to divide the weld area and the parent material area into independent mesh areas, avoiding the errors and instability that may be caused by shared nodes. The system will automatically perform meshing according to the meshing parameters set by the user to ensure that the physical properties of each area can be simulated independently and accurately. The process also includes mesh density adjustment and mesh optimization. Especially in the case of complex geometric shapes and weld intersections, the system uses intelligent algorithms to ensure the uniformity and quality of meshing, thereby improving the accuracy and reliability of simulation calculations.

[0018] Step 5: Weld Bead and Component Merging

[0019] After completing the meshing of non-common nodes, enter the step of merging welds and components. Users can set the merging parameters of welds and components, including welding paths, welding process parameters (such as temperature field, heat input, welding speed, etc.). The system automatically merges welds and parent material components accurately based on these parameters to ensure the integrity and consistency of the simulation model. After merging, users can also further check and adjust the connection of the welding area to ensure that the physical properties of the welded joint are correctly reflected in the model. In addition, the system will automatically verify and optimize the process parameters to ensure that factors such as heat input and deformation of the weld during welding are reasonably incorporated into the simulation model, thereby providing more realistic and accurate simulation results.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) Automated processing and format conversion: The present invention can automatically identify and convert geometric files of different formats (such as STL, IGES, etc.) into a unified grid format, simplifying the user operation process and greatly improving work efficiency. Users do not need to manually convert formats, and the system can automatically process various file formats to ensure smooth import and processing of data.

[0022] (2) Intelligent meshing: The present invention automatically generates high-precision meshes based on the complexity of the imported CAD model and the meshing parameters set by the user. The meshing process not only takes into account the geometric shape, but also intelligently optimizes the distribution of the mesh to ensure the accuracy of the simulation and analysis results, especially in the case of complex structures and multiple weld intersections, which can effectively ensure the mesh quality and avoid calculation errors.

[0023] (3) Multi-format support and flexible selection: The present invention supports a variety of common geometry file formats and allows users to flexibly select the required surface and non-shared node meshing types. Regardless of whether the data comes from CAD, STL files, or other formats, the system is compatible and can process them smoothly, significantly improving the convenience and compatibility of operations and meeting the needs of different users.

[0024] (4) Accurate welding path creation: The present invention uses accurate welding path generation technology to intelligently solve the optimal welding path after determining key parameters such as weld material, tolerance, and unit size. This technology ensures the path accuracy during the welding simulation process, which not only improves the simulation efficiency, but also avoids errors caused by unreasonable paths, thereby improving the reliability of the welding process.

[0025] (5) Automatic merging of components and welds: The present invention can automatically merge multiple meshed components into a single entity to ensure the integrity of the simulation model. During the merging process, the system automatically adjusts the connection between the weld and the component to ensure that the physical properties of the weld area are correctly reflected, thereby optimizing the subsequent simulation and analysis process.

[0026] (6) High-precision finite element unit: The present invention uses a hexahedral finite element unit, which has higher accuracy and computational efficiency than a tetrahedral unit. The hexahedral unit can more accurately capture the physical properties of complex geometric shapes, further improving the accuracy of simulation analysis, especially in thermal stress, temperature field and deformation simulation.

[0027] (7) Customized meshing: The system of the present invention allows users to precisely refine specific areas of the imported CAD model according to actual needs, thereby improving the flexibility of meshing and simulation accuracy. Users can adjust the mesh fineness and distribution according to the special requirements of the welding part, thereby improving the reliability and accuracy of the simulation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0029] Figure 1 It is a flow chart of a gridding technology without common nodes according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The exemplary embodiments of the present invention will be described in more detail below in conjunction with the accompanying drawings. Although these exemplary embodiments show some specific implementation methods of the present invention, the scope of protection of the present invention is not limited to these embodiments. The provided embodiments are intended to fully demonstrate the technical concept of the present invention and provide a clear understanding framework for those skilled in the art. In actual application, for different simulation requirements and process conditions, the relevant technical solutions can be appropriately adjusted and optimized according to the overall technical concept of the present invention. Therefore, the present invention has strong adaptability and can be flexibly applied according to specific circumstances.

[0031] Under the premise of following the core technical concept of the present invention, the structure, performance, effect or other features of a specific embodiment can be flexibly combined and optimized with the technical solutions in other embodiments. This flexibility enables the present invention to provide customized solutions according to specific welding simulation requirements and process environment, thereby further improving simulation accuracy and calculation efficiency.

[0032] In the process of describing the specific embodiments, we will elaborate on the structure, performance, effect and other features in detail to help those skilled in the art to deeply understand the application and implementation of these embodiments. However, it should be emphasized that those skilled in the art can still reasonably adjust and apply the present invention in actual applications according to specific application scenarios and requirements without fully possessing the above-mentioned structure, performance or characteristics, so as to achieve the expected welding simulation effect and optimization goals.

[0033] As attached Figure 1 As shown, Figure 1 The flowchart of a non-common-node finite element meshing technology is shown. Taking a large steel structure welding simulation as an example, the structure contains multiple welds, and the geometric shapes of the welds and the parent material are complex. It is difficult to generate a high-quality mesh model using traditional common-node meshing technology. To solve this problem, the non-common-node meshing technology of the present invention is used, and the specific steps are as follows:

[0034] Step 101: Import the CAD model:

[0035] Import the CAD model of the large steel structure into the welding simulation software of this system. This step includes converting the CAD file into a format that the simulation software can recognize. During the import process, it may be necessary to clean up and repair the model to remove potential geometric errors or irregularities to avoid affecting the results of subsequent simulation analysis.

[0036] Step 102: Model surface construction

[0037] The imported CAD model is surface constructed to generate a geometric model suitable for non-common node meshing. This step includes analyzing the model's geometric features, identifying areas that need to be meshed, and selecting an appropriate surface construction method based on the complexity of the model. During the construction process, it may be necessary to simplify the model and reduce the number of meshes while ensuring that key geometric details are retained to ensure the accuracy of the simulation results.

[0038] Step 103: Welding Path Creation

[0039] Create welding paths on the constructed geometric model to clarify the location, shape and size of the weld. The creation of welding paths needs to consider factors such as welding sequence, welding process parameters and equipment limitations to ensure the feasibility of the welding process and enable the welding simulation to accurately reflect the actual working conditions. This step will also adjust the optimal layout of the welding path according to the simulation requirements to improve simulation accuracy and calculation efficiency.

[0040] Step 104: Meshing of non-common nodes:

[0041] The weld area and the base material area are meshed separately to generate independent mesh models, which is the core step of the present invention. By avoiding shared nodes between the weld and base material areas, meshing improves the independence of the meshes in each area, thereby improving the simulation accuracy. In order to achieve the connection between the weld and the base material, the system can use methods such as virtual nodes or spring units to ensure that the physical interaction between the two can be accurately simulated, avoiding the errors and instability caused by traditional common node technology.

[0042] Step 105: Weld bead and component merging

[0043] The weld mesh model and the parent material mesh model are merged to form a complete welding simulation model. After completing the welding path planning and meshing the geometry, the user can set the proximity tolerance and truncation coefficient. The system will automatically generate a welded solid model based on the set welding path and meshed geometry. This merging step ensures the accuracy and integrity of the welding process, and also lays a solid foundation for the subsequent analysis of physical phenomena such as stress and deformation.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A non-common-node finite element meshing technology, characterized by: The user first imports the geometry model, and when the welding path selection and weld bead entity merging functions are required, multiple component geometries must be imported. After importing the component geometry, the user needs to perform surface construction of the geometry. Unlike traditional common-node meshing methods, non-common-node meshing technology allows mesh generation without mandatory mesh node alignment, providing greater flexibility. In the subsequent welding path selection process, users can select welding paths according to the required parameters and material conditions. The system will automatically generate welds and optimize the welding path according to user-set parameters such as tolerance values ​​and unit sizes. After completing the welding path selection, users can use the weld entity merge function to merge the meshed geometry with the weld to generate the final welding entity model.

2. The method according to claim 1, characterized in that: The component geometry import function supports STL or K format files, and can import multiple component geometries at the same time. The imported component geometries will be presented in VTK format files and CDF format files, where VTK format files are displayed in three-dimensional form.

3. The method according to claim 1, characterized in that: In the surface construction stage, the system requires the user to first select the geometry to be processed and specify its material properties. When planning the welding path, the simulation needs to complete the following steps through the visual interactive interface of this system: 1) Select the upper welding structure and the lower base structure in turn; 2) Accurately locate the starting point, intermediate path point and end point coordinates of the welding trajectory; 3) Configure welding material parameters. At the same time, the following process parameter groups need to be entered: tolerance parameters (including margin tolerance, face distance tolerance), mesh control parameters (unit size, center refinement area diameter), weld feature parameters (standard weld radius, number of arc surface units, number of multi-layer welds), and path optimization parameters (starting end offset, ending end offset). After the parameter configuration is completed, the system will automatically generate a weld structure that meets the process requirements based on the preset algorithm, thereby achieving precise welding connections between component geometries.

4. The method according to claim 1, characterized in that: The solid meshing process adopts the non-common node technology. The user needs to select the geometry and the mesh type suitable for non-common node simulation, and set the corresponding parameters according to the selected mesh type to ensure the mesh independence between the weld and the base material, thereby improving the simulation accuracy and calculation efficiency.

5. The method according to claim 1, characterized in that: The mesh types include PQSurface, SheetMetalCircularPatch, MeshCylinder, PQSurfaceCircularPatch, PQSurfaceWithInnerHoles and other mesh types designed for non-common-node welding simulation. These mesh types can adapt to different welding structures and process requirements while maintaining the independence of weld and base material meshes.

6. The method according to claim 1, characterized in that: The weld entity merging function adopts non-common node technology and requires the user to input the proximity error and truncation coefficient. The system will automatically generate the welded entity model based on these parameters, welding path and meshed entity, while ensuring the accuracy and independence of the mesh connection between the weld and the base material.

7. The method according to claim 1, characterized in that: The geometry import process includes automatic format conversion of the imported files. All imported files will be automatically converted to stl.cdf format suitable for non-shared node simulation. If the STL format file is imported, the system will automatically read and generate the stl.cdf format file; while the K format file needs to be meshed to generate the stl.cdf format file suitable for non-shared node simulation.

8. The method according to claim 1, characterized in that: The system provides a custom meshing function. Users can choose to perform custom meshing on parts of a specific geometry and set the maximum and minimum unit lengths to meet the needs of non-shared node simulations and ensure mesh independence between the weld and the parent material.

9. The method according to claim 1, characterized in that: The system supports multi-level welding path planning. Users can set different parameters for welding paths at different levels, including the number of weld layers, material properties, and unit size, to meet the simulation requirements of non-shared nodes and ensure the accuracy and independence of the mesh connection between the weld and the base material.

10. The method according to claim 1, characterized in that: The system supports automated welding path optimization functions. The system will automatically adjust the welding path according to the shape of the geometry and the parameters input by the user to reduce welding stress and deformation, improve welding quality, and ensure the accuracy and efficiency of the non-shared node simulation process.

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